Split-ring gland pipe coupling with corrugated armor

ABSTRACT

An annular gasket configured to seal a split-ring gland of a pipe coupling onto an end of a pipe having an annular outer gasket and a separate inner annular gasket. The outer gasket has an inner circumferential surface and the inner gasket has an outer circumferential surface, the circumferential surfaces being removably engaged. The inner gasket may be wider than the outer gasket to form a lip that projects beyond the outer gasket. The inner circumferential surface of the outer gasket and the outer circumferential surface of the inner gasket may include triangular shaped interdigitations configured to prevent axial movement between the gaskets.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/028,287 filed Feb. 16, 2011, the disclosure of which is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to pipe couplings and jointsand, more particularly, to pipe couplings adapted to couple and sealadjacent ends of two pipe sections of the same or different diameters.

BACKGROUND OF THE INVENTION

Conventional pipe couplings for coupling and sealing adjacent ends oftwo pipe sections include a coupling sleeve or collar with each pipe endextending into a respective end of the coupling sleeve. A gasket is heldadjacent each end of the sleeve overlying the pipe section. An annularflange or gland is associated with each gasket and end of the sleeve,and is tightened to draw down the gasket against the pipe end thussealing the pipe coupling thereto. One pipe coupling is shown in myprior U.S. Pat. No. 6,168,210 and utilizes continuous flanges that arecoupled together via bolts spanning the sleeve. The flanges, sleeveends, and gaskets have particular relationships that affect the seal andallow the coupling to work over a range of pipe sizes to compress thegaskets against the pipe ends as the flanges are drawn towards eachother.

While the continuous flange type of pipe coupling is considered to beparticularly advantageous, another style of pipe coupling is proposed inwhich each flange is provided by a split-ring gland that presents spacedapart confronting ends which can be drawn together with a bolt to closedown on the associated gasket. As a consequence, it is not necessary tohave bolts that span the sleeve, nor cause the glands to move towardseach other. Instead, each end of the sleeve can be independently coupledto the respective pipe end.

In order to work over a range of pipe diameters, the split-ring gland issized such that it circumscribes most of the circumference of the sleeveend and gasket, but not that portion in the gap defined between thespaced apart confronting ends. However, it is important that the gasketnot be exposed radially out of that gap as it will then be a source ofleakage and/or failure during installation. To that end, the split-ringgland type of pipe coupling includes a bridge plate or “armor” spanningthe gap over the gasket and extending into the gland at each end of thearmor. The armor is shaped to conform to the arc of the gland and gasketso as to, in effect, define a continuation of the gasket-confrontingsurface of the gland. Thus, as the gland is closed down, the gasket willshift and seat throughout the combined circumference of the gland andthe armor in order to facilitate installation and create the desiredseal.

SUMMARY OF THE INVENTION

The present invention in one aspect provides an improved armor for thesplit-ring gland type of pipe couplings. The conventional armor is coldformed of stainless steel and presents a generally flat, smooth surfaceto the outer periphery of the gasket. In accordance with the principlesof the present invention, at least a portion of the gasket confrontingsurface is corrugated, i.e., it is provided a plurality of corrugationsextending along the surface. The corrugations improves the performanceof the armor and, unexpectedly, also enhances the assembly of the pipecoupling. In that regard, the corrugations are advantageously instilledby cold working and therefore provides both increased bending stiffnessand tensile strength to the armor as compared to conventional armors.

Also, during installation with conventional armors, the gasket wouldtend to “bunch up” at the ends of the armor, making it difficult toproperly install the pipe coupling. In fact, the gasket and possibly thearmor might have to be heavily lubricated to facilitate the shifting ofthe gasket as the split-ring gland is compressed to help reduce the riskof bunching. But the lubrication further hampers installation as thecomponents are more difficult to handle and can hold dirt and otherdebris to the parts which is undesirable. Moreover, bunching was notalways avoided even with lubrication. Unexpectedly, the corrugations ofthe armor according to the present invention reduces or eliminates thetendency of the gasket to bunch up thereagainst and also allows thegasket to more readily shift as it is compressed by the gland. As aresult, the need for lubrication may be reduced, if not eliminated, thusfurther facilitating installation of the split-ring gland type ofcoupling.

By virtue of the foregoing there is thus provided by this one aspect ofthe present invention an improved armor for the split-ring gland type ofpipe couplings.

With some split-ring type of pipe couplings, the gland may be formed asa unitary ring, but must be made of sufficiently flexible material thatthe spaced apart ends at the gap can be stretched or pulled apart toopen up the gap in order to fit the gland onto the flange end of thesleeve. That design presents various drawbacks. Another proposal is toinstead couple the abutting ends of two gland members by a fastenerextending parallel to the longitudinal axis of the gland so that thegland members may “scissor” thereabout to increase the spacing of thegap from its nominal size for purposes of mounting the gland to theflange end of the sleeve. While the scissoring approach may facilitateassembly, for example, while using desirably more rigid materials, theability of the gland members to scissor presents its own drawbacks. Tothat end, and in accordance with a second aspect of the presentinvention, the split-ring gland of the present invention utilizes twogland members, but securely couples them along one side with a fasteneroriented tangential to the gland members. As a consequence, more rigidmaterials may be used, but without the disadvantage of scissoring.

Further, some split ring type of pipe couplings utilize a gasket havinga plurality of layers integrally connected to each other. The innerlayer typically defines an opening adapted to receive small pipe endstherethrough. Where it is desired to couple to a larger pipe end thancan fit through the inner layer opening, one or more of the layers maybe torn off the gasket to increase the size of the opening through thegasket to accommodate that larger pipe. Situations arise where thesmaller diameter opening provided by the inner layer(s) was desired. Butthe torn-off layer(s) cannot be reused necessitating that the gasket bediscarded and replaced with an entirely new gasket. In accordance with athird aspect of the present invention, a gasket is provided that iscomprised of two separate and reusably coupled layers. To that end, thegasket advantageously includes an outer gasket and an inner gasketincluding corresponding interdigitated surfaces adapted to reusablycouple the outer gasket and the inner gasket. The inner gasket may bewider axially than the outer gasket such that the inner gasket includeslips that may be gripped for pulling the inner gasket interdigitationsradially inwardly and away from the outer gasket interdigitations. Theinterdigitations may be symmetrical along an axial direction such thatthe inner gasket may be re-coupled with the outer gasket in a differentorientation rotated 180 degrees from an original orientation of theinner gasket.

The foregoing and other advantages of the present invention will beapparent in light of the accompanying drawings and detailed descriptionthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate an embodiment of the inventionand, together with the general description of the invention given aboveand the detailed description of the embodiment given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective view of a pipe coupling utilizing armors inaccordance with the principles of the present invention;

FIG. 2 is a perspective view of the pipe coupling of FIG. 1 for purposesof describing the use of the pipe coupling to sealingly couple two pipesin fluid communication;

FIG. 3 is partially-exploded perspective view of the pipe coupling ofFIG. 1;

FIG. 4 is a perspective view of one of the armors of FIG. 1;

FIG. 5 is an exploded perspective view of a gasket used with the pipecoupling of FIG. 1;

FIG. 6 is a partial cross-sectional view of one end of the pipe couplingof FIG. 1 taken along line 6-6 in FIG. 1 with one of the pipes of FIG. 2inserted into the pipe coupling;

FIG. 7 is an enlarged partial cross-sectional view of one end of thepipe coupling and pipe of FIG. 6, showing details of the gasket andarmor thereat; and

FIG. 8 is an enlarged partial cross-sectional view of one end of thepipe coupling and pipe of FIG. 6, including a different gasketconfiguration.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 2, a split-ring gland type of pipecoupling 10 according to one embodiment of the present invention isshown. The pipe coupling 10 includes a sleeve 12, a pair of split-ringglands 14, a bridge plate or armor 16 associated with each split-ringgland 14, and an annular gasket 18 associated with each split-ring gland14. In the fully assembled state of the pipe coupling 10, an end E1 of afirst pipe P1 is inserted into the sleeve 12 through one of thesplit-ring glands 14 and the corresponding gasket 18, and an end E2 of asecond pipe P2 is inserted into the other split-ring gland 14 andassociated gasket 18. The split-ring glands 14 are configured to betightened onto the corresponding gaskets 18 to compress the gaskets 18into sealing connection with the respective pipe ends E1, E2. Thesplit-ring gland 14 and the armor 16 collectively define a generallyclosed annular periphery 19 around the gasket 18, which further ensuresthat fluid passing through the pipes P1, P2 and the pipe coupling 10does not leak past the gasket 18 out of the pipe coupling 10. Thus, thepipe coupling 10 provides a sealed coupling of two adjacent pipe endsE1, E2 in fluid communication.

Further details of the components of the pipe coupling 10 are shown inFIG. 3, in which one of the split-ring glands 14 is shown partiallyexploded to facilitate discussion. The sleeve 12 includes a generallycylindrical body portion 20 defining a longitudinal axis LA of the pipecoupling 10 and having opposing open ends 22. At each of the opposingends 22, the sleeve 12 further includes a radially outwardly-directedflange 24 that is used to accurately locate the split-ring gland 14 andthe annular gasket 18, as described in further detail below. Althoughthe sleeve 12 of the exemplary embodiment is shown as cylindrical, itwill be understood that the body portion 20 of the sleeve may also betapered slightly inwardly adjacent both open ends 22 to provideclearance for slight angles between the pipe ends E1, E2 to be coupledin fluid communication by the pipe coupling 10.

Each of the split-ring glands 14 includes a first partially-circulargland member 26 a and a second partially-circular gland member 26 b. Thegland members 26 a, 26 b each define a half-moon shape and areconfigured to be centered about the longitudinal axis LA of the pipecoupling 10. The gland members 26 a, 26 b include respective abuttingends 28 a, 28 b and respective spaced ends 30 a, 30 b. The abutting ends28 a, 28 b are configured to be securely coupled together in generallygap-free relationship as shown in FIG. 1. With the abutting ends 28 a,28 b securely coupled, the spaced ends 30 a, 30 b define a nominal gap32 therebetween. To this end, the abutting end 28 a of the first glandmember 26 a includes a first abutting bolt flange 34 a projectingradially outwardly from the abutting end 28 a. Similarly, the abuttingend 28 b of the second gland member 26 b includes a second abutting boltflange 34 b projecting radially outwardly from the abutting end 28 b.

The first and second abutting bolt flanges 34 a, 34 b includecorresponding apertures 36 a, 36 b oriented tangential to the axis LAand configured to receive a fastener, for example, the bolt 38 and nut40 shown in FIG. 3. The bolt 38 extends through the apertures 36 a, 36 band is coupled to nut 40, such that the bolt 38 and the nut 40 are alsooriented generally tangential to the split-ring gland 14 in theillustrated embodiment of the pipe coupling 10. Consequently, when thebolt 38 and nut 40 securely couple the abutting ends 28 a, 28 b, thegland members 26 a, 26 b are restrained from pivotally rotating relativeto each other thereat such that the ends 30 a, 30 b are restrained fromscissoring apart beyond the nominal gap 32. The nominal gap 32 describedabove is thus generally considered the maximum length of gap of thesplit-ring gland 14. The first and second abutting bolt flanges 34 a, 34b may be provided with opposing countersinks (only 42 a shown in FIG. 3)facing away from one another and configured to receive the head 38 a ofthe bolt 38 and the nut 40 generally flush with the structure of thefirst and second bolt flanges 34 a, 34 b. However, the first and secondabutting bolt flanges 34 a, 34 b may be securely coupled by alternativefasteners or may include internal threading at the apertures 36 a, 36 bin other embodiments. Furthermore, the first and second abutting boltflanges 34 a, 34 b may be modified to be plate-shaped or anotherappropriate flange shape as well understood in the art.

The first and second gland members 26 a, 26 b also include spaced boltflanges 44 a, 44 b at the respective spaced ends 30 a, 30 b. The spacedbolt flanges 44 a, 44 b project radially outwardly from the spaced ends30 a, 30 b of the first and second gland members 26 a, 26 b. The spacedbolt flanges 44 a, 44 b include corresponding apertures (only 46 b shownin FIG. 3) configured to receive an adjustable fastener such as theelongate bolt 48 and nut 50 shown in FIG. 3. In this regard, the nut 50may be tightened on the elongate bolt 48 to draw the spaced bolt flanges44 a, 44 b and the spaced ends 30 a, 30 b closer together from thenominal position to a tightened position, to thereby compress theannular gasket 18 onto one of the pipe ends E1, E2. With the ends 28 a,28 b secured together as described above, tightening of the nut 50advantageously uniformly closes down the gland members 26 a, 26 b aboutthe annular gasket 18. The elongate bolt 48 and nut 50 are orientedgenerally tangential to the split-ring gland 14 in the illustratedembodiment of the pipe coupling 10. It will be appreciated that thespaced bolt flanges 44 a, 44 b may be coupled by alternative knownfasteners.

Each of the spaced bolt flanges 44 a, 44 b includes a convex arcuatesurface 52 a, 52 b facing the gap 32 between the spaced ends 30 a, 30 band a concave arcuate surface (only 54 a shown in FIG. 3) facing awayfrom the gap 32. The head 48 a of the elongate bolt 48 includes anarcuate surface 48 b configured to be received in the concave arcuatesurface 54 a of the first spaced bolt flange 44 a. A spacer 56 disposedadjacent the nut 50 also includes an arcuate surface 56 a configured tobe received in the concave arcuate surface of the second spaced boltflange 44 b. Consequently, when the nut 50 is tightened on the elongatebolt 48, the engagement of the head 48 a of the elongate bolt 48 withthe first spaced bolt flange 44 a and the engagement of the spacer 56with the second spaced bolt flange 44 b hold the elongate bolt 48 inposition with respect to the split-ring gland 14. One or more plastic ormetal washers 58 may also be provided between the spacer 56 and the nut50.

The first and second gland members 26 a, 26 b each include apartially-cylindrical annular wall 60 with an inner edge 62 and an outeredge 64. The partially-cylindrical annular walls 60 are generally flatrather than concave in cross section. The first and second gland members26 a, 26 b each further include an inwardly-directed U-shaped wall 66 atthe inner edge 62 of the annular wall 60. The U-shaped walls 66 areconfigured to receive the flange 24 at the end 22 of the sleeve 12,thereby accurately locating the split-ring gland 14 on the sleeve 12.The first and second gland members 26 a, 26 b each also include an outerwall 68 extending inwardly in a radial direction at the outer edge 64.As described in further detail below, at least a portion of the annulargasket 18 is captured between the outer walls 68 and the flange 24 ofthe sleeve 12. Thus, the annular walls 60, the outer walls 68, and theflange 24 of the sleeve 12 collectively define a gasket seat 69 for thesplit-ring gland 14. In the exemplary embodiment shown, the split-ringgland 14 may be tightened between a minimum diameter of about 10.00inches±0.13 inches and a maximum diameter of about 10.81 inches±0.25inches. The sleeve 12 and the split-ring gland 14 are each formed fromcarbon steel in one embodiment, but these components may alternativelybe formed from stainless steel, plastic, or another structural material.

The armor 16 is more clearly shown in FIGS. 3 and 4. The armor 16 isgenerally S-shaped in cross section and has an arcuate shape along itslength. The armor 16 includes a central wall 70 with an inner side edge72 and an outer side edge 74. The armor 16 also includes an inner sidewall 76 extending generally perpendicular to, and radially inwardly of,the central wall 70 at the inner side edge 72, and an outer side wall 78extending generally perpendicular to, and radially outwardly of, thecentral wall 70 at the outer side edge 74. The inner side wall 76 andthe outer side wall 78 extend in differing directions from the centralwall 70 to form the generally S-shaped cross section of the armor 16.The central wall 70 further includes lateral side edges 80 extendingfrom the inner side edge 72 to the outer side edge 74.

When the armor 16 is positioned at the gap 32 between the spaced ends 30a, 30 b of the gland members 26 a, 26 b, the central wall 70 ispositioned adjacent the annular walls 60 of the gland members 26 a, 26 bat the spaced ends 30 a, 30 b. To this end, the central wall 70 of thearmor 16 defines an arc length that is at least long enough to span thegap 32 such that the lateral side edges 80 of the central wall 70 aredisposed underneath the annular walls 60 of the gland members 26 a, 26 bin the nominal position of the split-ring gland 14. In this position,the inner side wall 76 projects into the U-shaped walls 66 of the glandmembers 26 a, 26 b, and the outer side wall 78 is positioned adjacentthe outer walls 68 of the gland members 26 a, 26 b at the spaced ends 30a, 30 b. Thus, the armor 16 and the split-ring gland 14 collectivelydefine a closed ring or loop for receiving the annular gasket 18. Morespecifically, the central wall 70 of the armor 16 cooperates with theannular walls 60 of the gland members 26 a, 26 b to collectively definethe generally closed annular periphery 19 for the annular gasket 18. Inthe exemplary embodiment, the armor 16 is configured to cover at leastabout 15% to about 30%, and advantageously, about 20% of thecircumference of the gasket 18 when the gasket 18 is installed in thesplit-ring gland 14.

Shown most clearly in FIG. 4, the central wall 70 includes a pluralityof corrugations 82 extending between the lateral side edges 80 andgenerally parallel to the inner and outer side edges 72, 74.Advantageously at least three or four such corrugations may be provided,although more or fewer may be provided depending on the width of thecentral wall 70 between the inner and outer side edges 72, 74.Furthermore, corrugations 82 advantageously extend radially outwardlyfrom central wall 70, but could additionally or alternatively extendradially inwardly therefrom. In any event, the corrugations 82 may beseen as defining a corrugated portion 82′ of the armor 16. The armor 16may be formed by cold forming stainless steel, although the armor 16 maybe formed in other ways. In that regard, at least corrugations 82 of theexemplary embodiment are advantageously instilled in the armor 16 bycold forming. The cold forming process provides increased structuralstrength for the armor 16, including increased tensile strength and workhardening. Furthermore, the corrugations 82 provide increased bendingstiffness and an improved mechanical performance in the assembly of thepipe coupling 10. The corrugations 82 reduce the surface area of thecentral wall 70 that contacts the annular walls 60 of the split-ringgland 14 and the annular gasket 18. As such, the armor 16 more freelymoves or slides with less friction against the split-ring gland 14 andthe annular gasket 18 when the split-ring gland 14 is tightened tocompress the annular gasket 18. In this regard, less lubrication or nolubrication is necessary between these components of the pipe coupling10 in operation.

Corrugations 82 each advantageously taper as at 84 into the central wall70 so as to stop short of either or both of the lateral side edges 80and are also generally inboard of the inner and outer side edges 72, 74so as to define one or more non-corrugated portions 85. Thenon-corrugated portions 85 extend inwardly from respective ones of theinner side edge 72, the outer side edge 74, and/or the lateral sideedges 80 toward the corrugations 82. Where non-corrugated portions 85are provided between each of the edges 72, 74, and 80, they cooperateto, in effect, define a frame about the corrugations 82. Advantageously,the corrugations 82 do not extend into one or both of the lateral sideedges 80, such that the lateral side edge(s) 80 provide a linear edgefor the armor 16 to confront and slide between the annular walls 60 ofthe split-ring gland 14 and the annular gasket 18. It will beappreciated, however, that working of the armor 16 to instill thecorrugations 82 may cause some portions of the lateral side edge(s) 80to distort. Moreover, the tapers 84 may extend into or against thelateral edge(s) 80 or the corrugations 82 may extend all the way to thelateral sides edge(s) 80. Unexpectedly, the inclusion of thecorrugations 82, especially where they stop short of the lateral sideedges 80, reduces the tendency of the elastomeric material of theannular gasket 18 to bunch up at the lateral side edges 80. Thus, thecorrugations 82 significantly improve the performance of the armor 16 ascompared to conventional, completely uncorrugated bridge plates orarmors.

The annular gasket 18 of the exemplary embodiment is further illustratedin FIGS. 5 through 7. The annular gasket 18 includes an annular outergasket 86 and a separate annular inner gasket 88 reusably coupled to(i.e., repeatedly insertable into and removable from) the outer gasket86. The annular gasket 18 defines a gasket opening 89 b therethroughcentered on the longitudinal axis LA when the pipe coupling 10 isassembled. Each of the outer gasket 86 and the inner gasket 88 arecomposed of an elastomeric material such as rubber. The outer gasket 86is configured to engage the split-ring gland 14 and the armor 16 alongan outer circumferential surface 90, and has an inner circumferentialsurface 92 configured to engage either the inner gasket 88 or therespective pipe end E1, E2 (when the inner gasket 88 is removed). Theinner gasket 88 is configured to engage the pipe end E1, E2 insertedinto the pipe coupling 10 and the inner circumferential surface 92 ofthe outer gasket 86 as will be described in greater detail below.

As shown most clearly in FIGS. 6 and 7, the outer gasket 86 includes theouter circumferential surface 90 facing the gland members 24 a, 24 b andthe inner circumferential surface 92 facing the inner gasket 88 (or therespective pipe end E1, E2 when the inner gasket 88 is removed). Theinner circumferential surface defines a first opening 89 a (FIG. 5)having a diameter D1. The outer gasket 86 also includes an inner sidesurface 94 extending between the outer and inner circumferentialsurfaces 90, 92 and facing the sleeve 12, and an outer side surface 96extending between the outer and inner circumferential surfaces 90, 92and facing away from the sleeve 12. The outer circumferential surface 90may be beveled such that the inner side surface 94 is longer than theouter side surface 96 to form a wedge-shaped configuration for the outergasket 86. Similarly, the inner gasket 88 includes an outercircumferential surface 98 facing the outer gasket 86 and an innercircumferential surface 100 facing the pipe end E1, E2 or in an inwardradial direction. The inner circumferential surface defines an opening89 b (FIG. 5) having a second, smaller diameter D2.

The inner gasket 88 may be selectively disengaged from the outer gasket86 and removed from the pipe coupling 10 to modify an effective range ofpipe outer diameters that may be sealed by and accommodated within thepipe coupling 10. In other words, the removable inner gasket 88 enablesmodification of an effective diameter of the pipe coupling 10 at thesplit-ring gland 14. For example, diameter D2 may allow the pipecoupling 10 to receive a pipe end E1 or E2 having an outer diameter (OD)in the range of 6.56 inches to 7.05 inches due to the presence of theinner gasket 88. However, removal of the inner gasket 88 leaves theopening 89 a of diameter D1 which may allow the pipe coupling 10 to thusreceive a pipe end E1 or E2 having an OD in the range of 7.05 inches to7.65 inches. As will be appreciated, however, the diametrical dimensionsand ranges of the split-ring gland 14 and the gasket 18 may be modifiedin other embodiments for pipes of different size ranges.

To facilitate reusable coupling of the inner gasket 88 to the outergasket 86, the outer gasket 86 and the inner gasket 88 havecorresponding interdigitated surfaces. More particularly, the innercircumferential surface 92 of the outer gasket 86 includes a pluralityof first interdigitations 102 configured to engage a correspondingplurality of second interdigitations 104 formed on the outercircumferential surface 98 of the inner gasket 88. The engagement of theinterdigitations 102, 104 discourages relative axial movement betweenthe inner and outer gaskets 88, 86. The interdigitations 102, 104 areconfigured to be symmetrical such that the inner gasket 88 and the outergasket 86 may be engaged without regard to orientation of the innergasket 88. More specifically, the inner gasket 88 may be inserted intothe outer gasket 86 in a first orientation along the longitudinal axisLA or a second orientation along the longitudinal axis LA wherein theinner gasket is reversed from the first orientation.

Also, because the outer gasket 86 and the inner gasket 88 are heldtogether merely by the interdigitations 102, 104, the inner gasket 88may be readily removed from and reinserted into the outer gasket 86 ifthe pipe end E1, E2 to be engaged by the annular gasket 18 has an ODwithin the smaller range provided above. For example, if a user (notshown) concludes that diameter D2 is too small for the intended pipe endE1 to be sealed by the pipe coupling 10, the inner gasket 88 may beremoved by grabbing the inner gasket 88 along any side and pullingradially inwardly such that the interdigitations 102, 104 disengagealong that side. The inner gasket 88 may then be pulled or torqued outof engagement with the remainder of the outer gasket 86 by pulling thepartially-disengaged inner gasket 88 along the longitudinal axis LA outof the outer gasket 86. If, upon further examination, it is determinedthat diameter D1 is too large, and diameter D2 would actually suffice,the inner gasket 88 may be recoupled to the outer gasket 86 by reversingthe steps described above.

In the illustrated embodiment, the first interdigitations 102 includeseveral triangular cross-section annular grooves: two triangular-shapedshallow grooves 102 a adjacent outer edges of the ring, two deepertriangular-shaped grooves 102 b inboard of the outer shallow grooves 102a, and two additional triangular-shaped shallow grooves 102 c inboard ofthe deeper grooves 102 b. It will be appreciated that firstinterdigitations 102 may alternatively be formed with different shapes(i.e., circular), different depths (i.e., all grooves having a uniformdepth), and with different numbers of grooves as opposed to theembodiment shown. In another alternative embodiment, the firstinterdigitations 102 may include a single concave smooth surface at theinner circumferential surface 92 of the outer gasket 86. Likewise, thesecond interdigitations 104 include several triangular cross-sectionannular projections 104 a, 104 b, 104 c sized and positioned to matewith the shallow and deeper grooves forming the illustrated firstinterdigitations 102. It will be further appreciated that other types ofprojections or a single smooth concave surface could be provided forsecond interdigitations 104 to match the various alternatives describedabove for the first interdigitations 102. Alternatively, the firstinterdigitations 102 may be projections and the second interdigitations104 may be grooves in other embodiments.

By positioning the inner gasket 88 within the outer gasket 86 with theprojections 104 aligned with the grooves 102, the outer and innergaskets 86, 88 are held together by their own resiliency, although thegaskets 86, 88 may be easily separated by pulling the inner gasket 88inwardly in a radial direction and then away from the outer gasket 86.To this end, the inner gasket 88 is generally wider in an axialdirection than the corresponding axial width of the outer gasket 86. Theinner gasket 88 therefore includes lips 106 projecting beyond the innerand outer side surfaces 94, 96 of the outer gasket 86, the lips 106facilitating easy gripping and movement of the inner gasket 88 inwardlyradially away from the outer gasket 86 when the inner gasket 88 is to beremoved from the pipe coupling 10.

The inner circumferential surface 100 of the inner gasket 88 isgenerally smooth or planar such that the inner gasket 88 provides areliable seal on the pipe end E1 or E2 sized to work with diameter D2and composed of various materials. However, the inner circumferentialsurface 100 may be provided with ribs, projections, or grooves similarto the interdigitations 102, 104 to provide an improved sealingconnection with the pipe end E1 or E2 formed from semi-porous materialsuch as cement. Similarly, with inner gasket 88 removed for use with thepipe end E1 or E2 sized to work with diameter D1, the firstinterdigitations 102 on the inner circumferential surface 92 of theouter gasket 86 may also improve the sealing connection with the pipeend E1 or E2 formed from semi-porous material. With any of thesealternatives, the split-ring gland 14 is configured to be tightenedsufficiently such that the inner gasket 88 or the outer gasket 86 formsa reliable seal around the corresponding pipe end E1, E2.

As shown in FIG. 7, the outer gasket 86 is configured to seat securelywithin the gasket seat 69 formed by the split-ring gland 14, the armor16, and the flange 24 of the sleeve 12. In operation, the outercircumferential surface 90 of the outer gasket 86 seats against theannular walls 60 of the gland members 26 a, 26 b and the central wall 70of the armor 16. The inner side surface 94 of the outer gasket 86 ispositioned adjacent to the flange 24 of the sleeve 12, and the outerside surface 96 of the outer gasket 86 is positioned adjacent to theouter walls 68 of the gland members 26 a, 26 b and the outer side wall78 of the armor 16. When the split-ring gland 14 compresses the outergasket 86 inwardly, the outer gasket 86 seals the pipe coupling 10 fromleakage adjacent the flange 24 of the sleeve 12 and adjacent thesplit-ring gland 14.

The outer gasket 86 may also include a nominally-open, nearlyhorizontal, annular slot 108 extending into the outer gasket 86 from theinner side surface 94 and towards the outer side surface 96. The slot108 is advantageously continuous and angled at a shallow angle (e.g.,8.5°) from a plane 109 defined by the inner circumferential surface 92,and angled such that the slot 108 traverses radially inwardly as theslot 108 extends from the inner side surface 94 towards the outer sidesurface 96. The slot 108 is advantageously continuous and uninterruptedabout the gasket opening 89 b at the inner side surface 94. The slot 108is positioned to aim towards the sleeve 12 and faces the correspondingflange 24 of the sleeve 12. Consequently, if pressurized fluid in thepipes P1, P2 begins to pass between the inner side surface 94 of theouter gasket 86 and the flange 24 on the sleeve 12, the pressurizedfluid will enter the slot 108 and press outwardly on the outer gasket 86at the slot 108. This additional force applied at the slot 108 furtherenhances the sealing connection of the outer gasket 86 to the split-ringgland 14, the armor 16, and the flange 24 of the sleeve 12. The angleand orientation of the slot 108 may be modified in other embodiments.

In the exemplary embodiment of the outer gasket 86 shown in FIG. 7, theslot 108 may have a length of approximately 0.75 inches when the outergasket 86 has an axial width of 1.25 inches. The first interdigitations102 or grooves may be spaced at regular 0.2 inch intervals and maydefine internal angles of about 40° to 45°. Additionally, the radialthickness of the outer gasket 86 may be in the range of about 0.75inches to 1.0 inch. The radial thickness of the inner gasket 88 may beabout 0.25 inches to enable the differing pipe OD ranges describedabove. It will be understood that these exemplary dimensions may bemodified for differing sizes of pipe ends E1, E2 and pipe couplings 10.

With reference to FIG. 8, another embodiment of an outer gasket 112 foruse with the inner gasket 88 is shown. The outer gasket 112 of thisembodiment again includes an outer circumferential surface 114, an innercircumferential surface 116, an inner side surface 118, and an outerside surface 120. Once again, the inner circumferential surface 116includes the plurality of first interdigitations 102 to enable couplingwith the inner gasket 88 as previously described. In contrast with theprevious embodiment, the inner side surface 118 and the outer sidesurface 120 are of the same length such that the outer gasket 112defines a generally rectangular shape. Additionally, the nearlyhorizontal slot 108 is omitted and an angled slot 122 is added. Theangled slot 122 extends into the gasket 112 at the junction 123 betweenthe outer circumferential surface 114 and the outer side surface 120 atabout an angle of 45° from each of the outer circumferential surface 114and the outer side surface 120. As the split-ring gland 14 is tightened,the gland members 26 a, 26 b tend to rotate slightly in cross sectionsuch that the outer side edge 120 of the outer gasket 112 is slightlymore compressed than the inner side edge 118 of the outer gasket 112.The angled slot 122 utilizes this uneven compression to create a wedgingaction on the portion of the outer gasket 112 disposed inwardly from theangled slot 122, which thereby improves the sealing connection of theannular gasket 18. In all other regards, the outer gasket 112 of thisembodiment operates similarly as the outer gasket 86 of the previousembodiment.

Although the angled slot 122 is angled at a relatively steep angle(e.g., 45°) from the outer circumferential surface 114, the angle andorientation of the slot 122 may be modified in other embodiments. In theembodiment of the outer gasket 112 shown in FIG. 8, the angled slot 122may have a length of approximately 0.875 inches when the outer gasket112 has an axial width of 1.25 inches. The first interdigitations 102 orgrooves may be spaced at regular 0.2 inch intervals and may defineinternal angles of about 40° to 45°. Additionally, the radial thicknessof the outer gasket 112 may be in the range of about 0.75 inches to 1.0inch. It will be understood that these exemplary dimensions may bemodified for differing sizes of pipe ends E1, E2 and pipe couplings 10.

To assemble the pipe coupling, two split-ring glands 14 are assembledwith the armors 16 and the gaskets 18 on the opposing open ends 22 ofthe sleeve 12. For each of the split-ring glands 14, the two glandmembers 26 a, 26 b are brought together such that the U-shaped wall 66of the split-ring gland 14 is engaged or seated onto the flange 24 atone open end 22 of the sleeve 12. The abutting ends 28 a, 28 b of thegland members 26 a, 26 b are securely coupled in gap free relationshipwith the bolt 38 and nut 40. Securely coupling the abutting ends 28 a,28 b in this manner will provide a nominal gap 32 between the spacedends 30 a, 30 b. The bolt 38 and nut 40 are oriented tangential to thegland members 26 a, 26 b and therefore restrain the gland members 26 a,26 b from scissoring outwardly at the spaced ends 30 a, 30 b andincreasing the length of the gap 32 from the nominal. The armor 16 isinserted to span the gap 32 between the spaced ends 30 a, 30 b of thegland members 26 a, 26 b and to form a generally closed annularperiphery 19 with the gland members 26 a, 26 b. The annular gasket 18 isinserted into the closed annular periphery 19 of the armor 16 and thefirst and second gland members 26 a, 26 b. Alternatively, the armor 16may be sitting on the gasket 18 and the gland members 26 a, 26 b may bebrought together over the flange 24, the armor 16, and the gasket 18simultaneously. In this position, the gasket 18 engages the corrugatedportion 82 of the armor 16. The spaced ends 30 a, 30 b may be coupled bythe elongate bolt 48 and nut 50. The elongate bolt 48 and nut 50 may beloosely engaged to leave the nominal gap 32 or, alternatively, may betightened to begin compressing the gasket 18. The pipe coupling 10 maybe packed and shipped in this assembled state in one embodiment.

Alternatively, each of the split-ring glands 14 may be assembled withthe corresponding armor 16 and gasket 18 as described above withoutseating the U-shaped wall 66 of the split-ring gland 14 onto the flange24 of the sleeve 12. In this assembly, the split-ring glands 14 may beshipped separately from the sleeve 12 and may be assembled with thesleeve 12 at a jobsite. The split-ring glands 14 will need to beloosened and mounted on the corresponding flanges 24 of the sleeve 12 atthe jobsite in these embodiments. Any of the above-described assemblysteps may be undone and repeated as required during installation and/orremoval of the pipe coupling 10.

In use, the assembled pipe coupling 10 is operable to couple the pipeend E1 into fluid communication with the pipe end E2. With reference toFIG. 2, the pipe end E1 of the first pipe P1 is inserted through thegasket opening 89 of a first split-ring gland 14 and through one openend 22 into the sleeve 12 (arrow 134). The pipe end E2 of the secondpipe P2 is inserted through the gasket opening 89 of a second split-ringgland 14 and through the other open end 22 into the sleeve 12 (arrow135). The elongate bolt 48 and nut 50 of the first split-ring gland 14is tightened to shorten the gap 32 between the spaced ends 30 a, 30 bthereof (arrows 136) and thereby generally uniformly compress thecorresponding annular gasket 18 into sealed engagement with the firstpipe P1. The elongate bolt 48 and nut 50 of the second split-ring gland14 is tightened to shorten the gap 32 between the spaced ends 30 a, 30 bthereof (arrows 137) and thereby generally uniformly compress thecorresponding annular gasket 18 into sealed engagement with the secondpipe P2. Each pipe P1, P2 may be inserted into the sleeve 12 prior totightening the split-ring glands 14, or one pipe (e.g., P1) may beinserted and tightened into position before the other pipe (e.g., P2) isinserted and tightened into position. Advantageously, the corrugations82 of the armors 16 reduce the frictional engagement of the armors 16with the corresponding annular gaskets 18 as the gaskets 18 arecompressed. Thus, the annular gaskets 18 do not tend to bunch up on thearmors 16 even with minimal lubrication in the split-ring glands 14.

In some applications, the first pipe P1 may be of a smaller diameterthan the second pipe P2. To accommodate the larger diameter pipe (e.g.,P2), the inner gasket 88 of the annular gasket 18 may need to beremoved. The corresponding interdigitations 102, 104 of the inner gasket88 and the outer gasket 86 are disengaged from each other so that theinner gasket 88 may be removed from the split-ring gland 14. Moreparticularly, the inner gasket 88 is pulled radially inwardly away fromthe outer gasket 86 along any side so that the correspondinginterdigitations 102, 104 are disengaged thereat. The inner gasket 88may then be pulled along the longitudinal axis LA to torque theremainder of the interdigitations 102, 104 out of engagement as theinner gasket 88 moves away from the outer gasket 86. The larger pipe P2may be inserted through the gasket opening 89 defined by the outergasket 86 and through the open end 22 of the sleeve 12, and thecorresponding split-ring gland 14 may tightened the outer gasket 86 intosealing engagement with the larger pipe P2. If a larger pipe is to bereplaced with a smaller pipe, or if it is determined that the largerpipe is not so large as to seal into just the outer gasket 86, the innergasket 88 may be re-inserted back into the outer gasket 86 by reversingthe disengagement steps described above to accommodate the smallerdiameter. The inner gasket 88 may be inserted back into the outer gasket86 in the original orientation or in a reversed orientation along thelongitudinal axis LA of the pipe coupler 10 because the correspondinginterdigitations 102, 104 are symmetrical. Each of these steps may berepeated to use the pipe coupling 10 on pipes P1, P2 of different sizes.

By virtue of the foregoing, there are thus provided an improved armor,an improved gland, and/or an improved annular gasket for the split-ringgland type of pipe couplings in accordance with various aspects of thepresent invention. While the present invention has been illustrated bythe description of embodiments thereof, and while the embodiments havebeen described in considerable detail, it is not intended to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. For example, an improved armor in accordance withthe principles of the first aspect of the present invention may be usedwith the improved gland and/or improved annular gasket, but could alsobe used with other glands or gaskets. Moreover, each of the improvedgland and the improved annular gasket in accordance with other aspectsof the present invention may be used independently of each other. By wayof further example, the armor and/or the corrugations 82 may be formedby hot working instead of cold working as will be appreciated by thoseskilled in the art. In regard to the gaskets, a generally solid outergasket with no angled slots may be provided in other embodiments of thepipe coupling. Further, only a single gasket rather than a gasket 18comprised of inner and outer gaskets, may be used. Additionally, theabutting ends 28 a, 28 b of the gland members 26 a, 26 b may be attachedin other ways, including with a longitudinal bolt or the like, althoughscissoring of the gland members 26 a, 26 b may result. Further, whileshown as being used to couple two pipe ends via the sleeve sleeve 12,only one end thereof might be provided with the split-ring glands 14,armor 16, and/or gasket 18. The invention in its broader aspects is,therefore, not limited to the specific details, representative apparatusand method, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thespirit or scope of the general inventive concept.

Having described the invention, what is claimed is:
 1. An annular gasketconfigured to seal a split-ring gland of a pipe coupling onto an end ofa pipe, the annular gasket comprising: an annular outer gasket includingan outer circumferential surface configured to engage said split-ringgland and an inner circumferential surface defining an opening of afirst diameter; and a separate annular inner gasket including an outercircumferential surface removably engaged with the inner circumferentialsurface of the outer gasket, and an inner circumferential surfacedefining an opening of a second, smaller diameter, the innercircumferential surface of the outer gasket and the outercircumferential surface of the inner gasket being configured toselectively engage so as reusably couple the inner and outer gasketswhereby to accommodate pipe ends of different diameters, the innergasket having a first axial width longer than a second axial width ofthe outer gasket, the additional axial width forming a lip on the innergasket that projects beyond the outer gasket.
 2. The annular gasket ofclaim 1, the inner circumferential surface of the outer gasket and theouter circumferential surface of the inner gasket each includingtriangular-shaped interdigitations configured to prevent relative axialmovement between the inner gasket and the outer gasket along alongitudinal axis through the gasket openings.
 3. The annular gasket ofclaim 1, the inner circumferential surface of the outer gasket and theouter circumferential surface of the inner gasket each includinginterdigitations configured to prevent relative axial movement betweenthe inner gasket and the outer gasket along a longitudinal axis throughthe gasket openings, the interdigitations being symmetrical along thelongitudinal axis such that the inner gasket is engageable with theouter gasket in a first orientation defined along the longitudinal axisand in a second orientation along the longitudinal axis wherein theinner gasket is reversed from the first orientation.
 4. The annulargasket of claim 1, the outer gasket including an inner side surfaceextending between the outer circumferential surface and the innercircumferential surface, the inner side surface including an inwardlyfacing angled slot.
 5. The annular gasket of claim 1, the outer gasketincluding an outer side surface extending between the outercircumferential surface and the inner circumferential surface, the outergasket further including an outwardly facing angled slot located at thejunction of the outer circumferential surface and the outer sidesurface.
 6. An annular gasket configured to seal a split-ring gland of apipe coupling onto an end of a pipe, the annular gasket comprising: anannular outer gasket including an outer circumferential surfaceconfigured to engage the split-ring gland and an inner circumferentialsurface defining an opening of a first diameter; and a separate annularinner gasket including an outer circumferential surface removablyengaged with the inner circumferential surface of the outer gasket, andan inner circumferential surface defining an opening of a second,smaller diameter, the inner circumferential surface of the outer gasketand the outer circumferential surface of the inner gasket beingconfigured to selectively engage so as reusably couple the inner andouter gaskets whereby to accommodate pipe ends of different diameters,the inner circumferential surface of the outer gasket and the outercircumferential surface of the inner gasket each includingtriangular-shaped interdigitations configured to prevent axial movementbetween the inner gasket and the outer gasket along a longitudinal axisthrough the gasket openings.
 7. The annular gasket of claim 6, whereinthe interdigitations on each of the outer gasket and the inner gasketinclude a first pair of interdigitations and a second pair ofinterdigitations positioned inboard from the first pair ofinterdigitations, the second pair of interdigitations being larger insize than the first pair of interdigitations.
 8. The annular gasket ofclaim 6, the outer gasket including an inner side surface extendingbetween the outer circumferential surface and the inner circumferentialsurface, the inner side surface including an inwardly facing angledslot.
 9. The annular gasket of claim 6, the outer gasket including anouter side surface extending between the outer circumferential surfaceand the inner circumferential surface, the outer gasket furtherincluding an outwardly facing angled slot located at the junction of theouter circumferential surface and the outer side surface.
 10. An annulargasket configured to seal a split-ring gland of a pipe coupling onto anend of a pipe, the annular gasket comprising an outer circumferentialsurface configured to engage the split-ring gland, an innercircumferential surface defining an opening, an outer side surfaceextending between the outer circumferential surface and the innercircumferential surface, and an inner side surface extending between theouter circumferential surface and the inner circumferential surface, theinner side surface including an nominally-open inwardly facing nearlyhorizontal, annular slot, the slot being continuous and uninterruptedabout the opening and being slightly angled from a plane defined by theinner circumferential surface such that the slot traverses radiallyinwardly from the inner side surface towards the outer side surface.